Auto-Zone Control Systems Auto-Zone Basic Systems User Manual

Design, Installation

Basic System

and Operations Manual

Revision 02C

Auto-Zone

Basic

Design, Installation & Operations Manual

Section 1..............................................................................System Overview

Section 2...................................................................Installation and Wiring

Section 3....................................................................................Programming

Section 4........................................................Start-Up and Troubleshooting

This document is subject to change without notice.

WattMaster Controls, Inc. assumes no responsibility

for errors, or omissions herein.

Auto-Zone Basic Installation & Operations Manual - Form WM-AZB-IO-02C

Auto-Zone is a registered trademark of WattMaster Controls, Inc.

Copyright 2009 WattMaster Controls, Inc.

All rights reserved.

Section 1

Table of Contents

Conventions .....................................................................1

General Information.........................................................3

Description of System Components.................................................................................3

Design Considerations.....................................................5

Zone Diversity .................................................................................................................5

Cooling - Partial Load Conditions ...................................................................................5

Heating - Partial Load Conditions ...................................................................................7

Override Conditions.........................................................................................................7

Building Pressurization....................................................................................................7

Design Guide....................................................................8

Step #1 - Zoning ..............................................................................................................8

Step #2 - Sizing the Central Unit ...................................................................................10

Step #3 - Duct Design Considerations...........................................................................10

Step #4 - Room Air Motion/Diffuser Selection.............................................................11

Step #5 - Bypass Damper Sizing ...................................................................................11

Step #6 - Sizing Zone Dampers .....................................................................................13

Round Dampers .............................................................................................................15

Rectangular Dampers.....................................................................................................15

Pressure Independent Zone Dampers ............................................................................16

Auxiliary Heat Control Options......................................17

Relay Expansion Board .................................................................................................18

Table of Figures & Tables

Figure 1-1: Auto-Zone Basic Control System...............................................................2

Figure 1-2: Control Zones Affected by the Outdoor Load ............................................9

Figure 1-3: Locating the Static Pressure Sensor for Bypass Damper Control ............12

Figure 1-4: Round Damper Dimensions......................................................................14

Figure 1-5: Rectangular Damper & Kit Dimensions...................................................14

Table 1-1: Round Air Damper Selection .....................................................................15

Table 1-2: Rectangular Damper Selection...................................................................15

Table 1-3: Pressure Independent Flow Factors............................................................16

Design Guide

Auto-Zone Basic

Section 1

Conventions

This document uses the following definitions throughout as a guide to the user in
determining the nature of information presented:

Note: Additional information which may be helpful

Tip: Suggestion to make installation, set-up, and troubleshooting easier.

Caution: Items which may cause the equipment not to function correctly, but will

not otherwise damage components.

Warning: Errors which can result in damage to equipment and void warranties.

Design Guide 1-1

Section 1

A

V

Auto-Zone Basic

To HVAC Unit
Control Panel

Supply

ir Temp

Sensor

Optional Remote Li nk II

Connects to CommLink IV

And Provides Alarm Call-Outs

A Second Remote Link Is Required

If Connection To Job Site

Is Desired From Remote Computer

Remote Link II

(Optional)

CommLink IV

The CommLink IV Is

Required For All Systems.

The IP Module, Remote

Link II, And Computer Are

Optional On All Systems.

All Computers Requ ire

Installation of Prism

Graphical User Interface

Software

USB Cable To Computer

Phone Cable To
Telephone
Wall Outlet Jack

CommLink IV

Single Loop

Economizer

(Actuator By Others)

Outside

Air Temp

Sensor

Computer

(Optional)

24VAC

Ethernet Cable To Router

Ethernet Router

(By Others)

When IP Module

Option Is Used

RS-485

9600 Baud

Optional IP Module

Installs Into CommLink IV

And Provides
LAN And Internet
Communications

With The Control System

Static

Pressure

Sensor

Zone Controller

elocity Sensor

(Optional)

Return

Air Temp

Sensor

Bypass Air

Damper

Typical Zone

Damper Actuator

Zone Air Dampers

Up to 16 Zone Air Dampers Allowed

#1

Room Sensor

with Optional

Override & Adj.

#16

RS-485

Comm Loop

24 VAC

Figure 1-1: Auto-Zone Basic Control System

1-2 Design Guide

Auto-Zone Basic

Section 1

General Information

The primary application of the Auto-Zone Basic Control System is to provide multiple
controlled comfort zones from a single zone, unitary heating and air-conditioning
package unit. It can also be applied to existing installations for improved comfort to
multiple zones currently controlled by a single thermostat.

Description of System Components

A typical Auto-Zone Basic Control System is comprised of the following four basic
components.

Zone Manager

The Zone Manager is a microprocessor-based controller which monitors up to 16 zones

in the system. The zone manager then controls the HVAC unit to satisfy the requirements
of each individual zone while maintaining efficient operation and comfort. The zone
manager is also responsible for controlling duct static pressure.

In the Auto-Zone Basic version, the Zone Manager has a display and a keypad. The 4­line by 20-character display is backlighted, making it easier to read in low light
environments.

Bypass Damper

The bypass damper controls proper duct static pressure to insure proper airflow. The

damper is modulated by the Zone Manager based on a signal received from the static
pressure sensor connected to the main duct.

Zone Controller

The Zone Controller monitors space temperature and allocates proper airflow to the

assigned zone to achieve desired comfort and ventilation levels. If supply air temperature
will benefit the local zone temperature setpoint, the zone damper modulates to reduce or
increase airflow as needed. If supply air will not benefit the local zone, the controller will
direct the damper actuator to a minimum position and wait for a change in supply air
temperature.

Design Guide 1-3

Section 1

Auto-Zone Basic

Zone Sensor

The patented zone sensor is a flush, wall-mounted design. A special plate on the face of

the sensor accurately senses space conditions. As a result of its unique design, the zone
sensor rejects the influence of internal wall temperature effects. The sensor comes in four
different configurations:

• Sensor only

• Sensor w/push-button override (override is fixed at 2 hours)

• Sensor w/setpoint adjustment

• Sensor w/override & setpoint adjustment

Any combination of these sensor configurations can be used with the system.

1-4 Design Guide

Auto-Zone Basic

Section 1

Design Considerations

Consider the following items when designing a system using Auto-Zone.

Zone Diversity

The Auto-Zone Basic Control System is designed to improve tenant comfort by
dynamically re-balancing the air distribution when used with a typical constant volume
rooftop heating/cooling unit. If zones with extremely different load conditions are
serviced by a single rooftop unit, the result will be poor control and excessive wear due
to cycling of the equipment.

It is especially important to avoid mixing interior zones (which require cooling all year)
with exterior zones (which may require constant heat during winter months). If you must
mix zones under these conditions, consider using either VAV boxes with heat or separate
baseboard heat on exterior zones. Auto-Zone Basic Control Systems offer a variety of
methods to control additional zone heat to help you avoid problems.

Cooling - Partial Load Conditions

The engineer must be aware of several potential problems when applying the Auto-Zone
Basic Control System during cold weather operation.

Low Ambient Temperature Lockout

During very cold weather it is common for mechanical systems to have “low temp
lockouts” which protect equipment from damage if operated under these conditions.
Auto-Zone also provides user programmed lockouts for protection purposes, although

mechanical safeties should always be used as the final stage of protection.

If the rooftop unit services interior zones with thermal loads which require cooling when
outside temperatures are below the safe operating limits for your equipment, you should
seriously consider installing an economizer on your rooftop unit. The Auto-Zone control
system is designed to take advantage of an economizer if it is installed. The use of an
economizer will save money on utilities and provide comfort under conditions when it is
not possible to operate the mechanical cooling system.

Low Supply Air Temperatures

Under lightly loaded conditions much of the supply air may be bypassed back into the
return airside of the system. This bypassing will result in the lowering of the supply air

Design Guide 1-5

Section 1

temperature, which may result in the supply air temperature reaching the low temp safety
limit. If the supply air low temp safety limit is exceeded, the control system will “cut-off”
the mechanical cooling to protect it from damage. Excessive cycling of the mechanical
system will result if this condition persists. Comfort may also suffer if the system cannot
run long enough to satisfy cooling demands.

A number of things can be done to reduce this problem. Some of these things depend
upon the type of installation.

• Avoid oversizing the unit. Do your load calculations carefully. Since Auto-Zone

directs the heating or cooling to the zones which require it, you may find that you can
use a smaller unit in many cases. Oversizing is the number one cause of excessive
low supply air temperature cycling.

• Increase your cooling minimum airflow or damper position settings to allow more air

during cooling operation. Be careful to avoid settings which are so high you cause
over cooling of the spaces. Find a compromise position.

• Bypass the air into the plenum instead of into the return air intake. Be careful if you

use this method since you may get “dumping” of cold air from your return air grilles.
This method works best with plenum returns. Do not use this method with ducted
returns unless you have carefully considered the consequences.

• Increase your static pressure setpoint to help reduce the amount of air being bypassed.

Be aware of increased noise levels and the cost of operation if you use excessive
static pressures.

Auto-Zone Basic

Warning: If the fan system has the capability of producing static pressures

which could damage ductwork, you must provide a manual reset high
pressure limit switch to cut-off the fan system in the event of high
duct static. Do not use your Auto-Zone Basic Control System as a
safety device!

• Use an Economizer. Although this is not a cure-all, it greatly improves operation

during cool weather when cooling loads are minimal. Using an Economizer also
improves ventilation and lowers operating costs, both of which are significant.

1-6 Design Guide

Auto-Zone Basic

Section 1

Heating - Partial Load Conditions

Heating difficulties are less common than cooling difficulties. They are similar in nature,
however, and the cures are generally the same.

• Increase the Heating minimum setpoints on as many zones as possible.

• Increase the static pressure setting as high as is practical. Increasing static pressure

does not help if you are using pressure independent operation.

• Bypass to plenum instead of the return air intake if acceptable.

• Do not oversize your equipment.

• Use auxiliary heat in either your VAV boxes or baseboard.

Auto-Zone has a number of auxiliary heat control options which provide solutions to

most problems. Refer to the Auxiliary Heat Control Options topic near the end of this

section.

Override Conditions

After-hours overrides can produce aggravated partial load conditions in both the heating
and cooling modes. The problem is most commonly caused by a single zone being
overridden for after-hours use. This causes the rooftop equipment to operate for only one
zone. The Auto-Zone Basic Control System offers an improved solution to this common
problem by allowing a single override to trigger a group of zones via a “global” override.
This allows the system to operate with sufficient load to reduce cycling caused by light
load conditions.

Building Pressurization

If you are using an economizer, building pressurization must be addressed. Failure to
properly handle building pressurization may result in doors remaining open when the
economizer is operating. Pressurization problems can render economizer operation
useless. The following suggestions will help to avoid potential problems.

• Use powered exhaust when the system uses ducted returns. The return duct pressure

drop will cause most barometric relief dampers to function poorly or not at all. Auto­Zone has the ability to control a powered exhaust whenever the economizer is
operating.

• Use a separate building pressure control which operates a relief fan or dampers.

Design Guide 1-7

Section 1

Auto-Zone Basic

Design Guide

There are six basic steps to designing an Auto-Zone Basic Control System:

1. Zoning

2. Sizing the Central Unit

3. Duct Design Considerations

4. Room Air Motion / Diffuser Selection

5. Bypass Damper Sizing

6. Sizing Zone Dampers

Step #1 - Zoning

Determine the number of zones. A single air handler unit can have no more than 16
zones. If the number of zones exceeds 16, then more than one Zone Manager will be
required. Consider using the Auto-Zone Plus system if more than one Zone Manager is
required.

The primary precaution to be taken in applying the Auto-Zone Basic Control System is to
select the zoning so that no zone will be at maximum (design) heating (or cooling) load
when any other zone requires the opposite temperature air to satisfy its load. For
example, depending on the wall, ceiling, floor material, and location within the building
(e.g. top or middle floor), a typical floor of a building usually has a minimum of 9
distinct temperature or control zones that are affected uniquely by the outdoor load.

These zones are depicted in Figure 1-2.

Depending on the size of the building and partition layout, some of these zones may
overlap or be insignificant from a zoning standpoint. For example, Zone 10 could be
multiple conference or computer rooms where additional zoning would be required, or it
could be as small as a corridor where no zoning is required. Similarly, zones 4 and 5
could have no external windows and no partitions between them and could be considered
a single zone. Zone 3 could be divided into multiple offices with full partitions between
them, thus requiring separate Zone Controllers because of different internal loads, but the
same external load.

Generally, the greater the number of individual Zone Controllers there are, the greater the
comfort. The designer will have to look at the specific building, balancing the costs of
multiple zones with the added comfort possible with multiple zones, to match the owner's
requirements.

1-8 Design Guide

Auto-Zone Basic

Section 1

It is important to recognize that there are purely internal zones, such as Zone 10, which
may contain separate offices/conference/computer rooms. These internal zones could
easily have high cooling requirements while external zones (1, 2, 3, etc.) could be at or
near design heating load. This is a misapplication of the Auto-Zone Basic or Plus (or any
heating/cooling changeover) system. The interior zones with cooling-only loads should
be served with a separate air-conditioning unit (that could be zoned between multiple
rooms with a similar load profile). Supplemental heat could be added to the perimeter
zones and controlled with the auxiliary heat control board from the Zone Controller.
System performance will generally be compromised and frequent changeover from the
heating to the cooling mode will occur during the heating season if purely internal zones
are combined on the same air-conditioning unit serving perimeter zones.

Zoned HVAC Unit

Supply Air Duct

Supply Air Duct

9

Constant Volume HVAC Unit

Return Air Plenum

Bypass Damper

System Manager

Round Zone Damper
(Typical)

Room Sensor

(Typical)

W

S

Return Air Plenum

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Figure 1-2: Control Zones Affected by the Outdoor Load

Design Guide 1-9

Section 1

Auto-Zone Basic

Step #2 - Sizing the Central Unit

Because the zones are controlled with variable air volume, it is unlikely that all zones
will be at design load at the same time. The zoning allows for the diversity of loads to be
taken into account and will often provide better comfort with a smaller HVAC unit.

In sizing the system, the individual zone loads should be calculated using any dependable
load estimating program. Because of diversity, the central unit should be selected for the
instantaneous peak load, not the sum of the peak loads, as would be done with a constant
volume single zone system. Consider the following when sizing the central unit.

• Size the peak cooling load based on the month and hour of the greatest total

building/system load.

• Heating should be sized for the lowest design temperature with an additional margin

for morning "pickup." This margin is generally recommended to be 20 to 25 percent
of base design.

Step #3 - Duct Design Considerations

The Auto-Zone Basic Control System uses a typical low pressure duct design. To reduce
noise problems, duct pressures should not exceed 1 inch W.C.

Primary trunk ducts should not be "undersized." This is especially true for "pressure
dependent" systems. Pressure dependent refers to the typical Auto-Zone Zone Controller
without the airflow sensor. With larger trunk ducts, it is easier to assure relatively constant
pressure to each zone. Runs should be as short as possible and the trunk duct system kept
as symmetrical as possible to facilitate system balancing. Wherever possible, run the trunk
ducts above corridors and locate the zone dampers above corridors to reduce the noise in
the space and facilitate service of the units. Trunk ducts should be sized for no more than

0.1 inch W.C. drop per 100 feet and a maximum duct velocity of 2000 FPM.

Note: For pressure independent terminal units with velocity sensors and

conventional "VAV" boxes properly selected for "quiet" operation, this 2000
FPM rule can be exceeded by up to 50 percent. The designer, however, should
be very experienced in VAV system design before considering modification
of this general rule.

Typical VAV systems with pressure independent terminals use the static regain method
for sizing ducts. The typical Auto-Zone Basic Control System is a low-pressure, pressure
dependent system that utilizes conventional unitary air-conditioning units. These systems
should use the equal-friction method of sizing the ducts and use the maximum loss of 0.1
inch per 100 feet as described above.

1-10 Design Guide

Auto-Zone Basic

Section 1

Step #4 - Room Air Motion/Diffuser
Selection

Air motion is a consideration for occupant comfort. The selection of diffusers for an
Auto-Zone Basic Control System requires more care than a constant volume system due
to varying flow of air into the zones. Slot diffusers are recommended due to their superior
performance at low airflows. Because the zone airflow is variable volume, lower cost
round or rectangular diffusers that were satisfactory for constant volume may prove
unsatisfactory with an Auto-Zone Basic Control System. These diffusers may result in
"dumping" of the cold air at low flows in the cooling mode and insufficient room air
motion at low air flows in the heating mode. Although high air motion in the heating
mode can be undesirable, a slot diffuser with a high induction ratio generally helps to
reduce room air "stratification" when the heating comes from a ceiling diffuser. Linear
slot diffusers should be properly selected for the airflow and "throw" suited to the
specific installation or zone.

Additional factors to consider in diffuser selection are sound level and throw at design
flow. Generally, multiple diffusers will result in lower sound levels in the space, but this
must be balanced with the additional hardware and installation costs. It is commonly
recommended that slot diffusers be located near the perimeter or outside wall with the
airflow directed into the room. Consult your diffuser supplier or catalog for proper
diffuser sizing and location.

Series fan boxes may be used instead of zone dampers where higher induction rates are
desirable. If the heat loss on perimeter walls is high, such as large areas of glass, the use
of Series Fan Boxes may be indicated to maintain higher induction rates to offset
“downdrafts.” If the heat loss is greater than 275 BTUH/LINEAR FOOT, you should use
high quality slot diffusers next to the outer wall with the airflow directed inward to
counteract downdrafts during heating. Serious downdraft problems occur when heat
losses exceed 400 BTUH/LINEAR FOOT. In such case, both high induction diffusers
and series fan boxes are recommended.

Step #5 - Bypass Damper Sizing

Using a load calculation program, the bypass damper should be sized to give you the
maximum CFM of air to be bypassed, typically 60 to 70 percent of the HVAC units rated
capacity. Bypass Dampers can either be round or rectangular depending on building or
job requirements. Use the appropriate round or rectangular damper selection table to
determine the correct damper size for your application. To size the damper, select a
damper from the table based on calculated bypass CFM and a maximum velocity
between 1750-2250 FPM. When determining the bypass duct size, be sure to take into

account any transition fittings and associated pressure drops. (See Table 1-1: Round
Damper Selection or Table 1-2: Rectangular Damper Selection.)

Design Guide 1-11

Section 1

Auto-Zone Basic

If space limitations or total airflow requires it, multiple bypass dampers can be controlled
in parallel. For proper control of the Bypass Damper, the static pressure sensor location is

very important. Refer to Figure 1-3: Locating the Static Pressure Sensor for Bypass
Damper Control below for proper mounting locations.

Preferred Location

If the trunk ducts are properly sized
for minimum pressure drop, the

Fan

location of the static pickup probe is
not particularly critical. It should
ideally be located at right angles to
the airflow in a straight section of the
supply duct approximately ⅔ the
distance of the total length of the
supply duct. Also, the probe should

SA Sensor

Bypass Damper

SPPickup

Supply Air Duct

RASensor

Return Air Duct

SP Sensor

be located not less than 3 duct
diameters downstream and 2 duct
diameters upstream of any elbow or

3D
Min.2DMin.

takeoff.

Less Than Ideal, But
Acceptable

Since the "ideal" location is often

Fan

difficult to find in an installation, a
location in the main trunk where
the tip is not in a "negative
pressure area" (e.g. just
downstream of the inside curve of

Supply Air Duct

SP Sensor

SA Sensor

SPPickup

Bypass Damper

RASensor

Return Air Duct

an elbow) or an area where the
tube opening is directly impacted
by the velocity of the supply air is
acceptable.

Least Desirable, But
Acceptable

If the supply duct comes directly
from the unit and immediately
splits in opposite directions, the
pressure pickup should be located
ahead of the split or as close to it

Supply Air Duct

TubingToBeEqual
LengthAnd Size

Fan

Bypass Damper

SA Sensor

RASensor

Return Air Duct

as possible, even if the bypass
damper(s) are located downstream
of the split.

SPPickups

SP Sensor

Figure 1-3: Locating the Static Pressure Sensor for Bypass Damper Control

1-12 Design Guide

Auto-Zone Basic

Section 1

Step #6 – Sizing Zone Dampers

Use a load program to determine the peak load for each zone. These calculations will be
used in selecting the appropriate zone damper sizes.

A round damper or rectangular damper can be selected depending on the building or job
requirements. If the job requires pressure independent damper control, the damper
selected must be a round damper. Rectangular dampers are not available for pressure

independent control. Please see Table: 1-1 for round damper selection. Please see Table:
1-2 for rectangular damper selection.

Using the maximum acceptable velocity for a branch duct (typically 1000-1500 FPM for
minimal noise), find the smallest damper that will deliver the required CFM as
determined by the load program.

Go to either the Round Damper Selection table (Table: 1-1) or the Rectangular Damper
Selection table (Table: 1-2) depending on your requirements to select the dampers.

Locate the branch velocity used in the duct design program on the left hand column of

either damper sizing chart (Table: 1-1 or Table: 1-2). Move across the chart and find the

damper which will provide the acceptable CFM to meet each zone’s airflow
requirements.

Note: Compare the damper size selected against the duct size to determine if the

next size up or down will provide acceptable performance without requiring a
transition fitting.

Up to two additional dampers may be slaved together for larger zones. See zone wiring
diagram for details. This should be reserved for situations when it is not practical to use a
single large damper.

Design Guide 1-13

Section 1

Note: Dimensions Are

Identical For Round Zone,
Bypass & Slave Dampers

Auto-Zone Basic

Figure 1-4: Round Damper Dimensions

Note: See Table 1-2 for

Available “A” x “B”
Rectangular Damper Sizes

Note: Dimensions Are Identical

For Rectangular Zone, Bypass &
Slave Dampers

Figure 1-5: Rectangular Damper & Kit Dimensions

1-14 Design Guide

Auto-Zone Basic

Section 1

Round Dampers

Round Air Damper Selection

Air Damper Round Duct Size

( Area Ft2 )

Velocity Through Round Air

Damper

(FPM)

750 - Zone
1000 - Zone
1250 - Zone
1500 - Zone

1750 - Bypass Only
2000 - Bypass Only
2250 - Bypass Only

Table 1-1: Round Air Damper Selection

6”

(0.188)

(0.338)

141 254 399 577 788 1031
188 338 532 769 1050 1375
235 423 665 961 1313 1718
282 507 798 1154 1575 2062
329 592 931 1346 1838 2405
376 676 1064 1538 2100 2749
423 761 1197 1730 2363 3094

8”

10”

(0.532)

12”

(0.769)

14”

(1.050)

Volume Through Round Air Damper

(CFM)

16”

(1.375)

Rectangular Dampers

Rectangular Damper Selection

Damper

Height

(B)

Damper

Width

(A)

8”
10”
12”
14”
16”
18”
20”
22”
24”
26”
28”
30”
32”
34”
36”

Table 1-2: Rectangular Damper Selection

Notes: 1.) Zone Dampers Should Be Sized Based On The Required Zone CFM. The Table Above Is

8” 10” 12” 14” 16” 18” 20” 22” 24” 26” 28” 30” 32” 34” 36”

Airflow Through Rectangular Damper

CFM @ 1000 FPM Velocity

410 530 640 740 850 970 1080 1190 1300 1410 1520 1630 1740 1850 1970
510 590 690 800 910 1030 1150 1260 1380 1500 1610 1730 1840 2000 2080
560 650 730 850 970 1090 1210 1330 1460 1580 1700 1820 1940 2060 2190
660 770 880 1030 1180 1330 1480 1630 1760 1910 2060 2210 2360 2510 2640
750 890 1030 1200 1370 1540 1710 1880 2060 2230 2400 2570 2740 2910 3090
770 980 1180 1380 1580 1780 1980 2180 2350 2550 2750 2950 3150 3350 3540
850 1090 1330 1550 1770 1990 2210 2430 2650 2870 3090 3310 3530 3750 3990
930 1210 1480 1730 1980 2230 2480 2730 2950 3200 3450 3700 3950 4200 4440
950 1290 1630 1900 2170 2440 2710 2980 3250 3520 3790 4060 4330 4600 4880

990 1390 1780 2080 2380 2680 2980 3280 3550 3850 4150 4450 4750
1070 1500 1930 2250 2570 2890 3210 3530 3850 4170 4500 4820
1020 1550 2080 2430 2780 3130 3480 3830 4150 4500 4850
1090 1660 2230 2600 2970 3340 3710 4080 4450 4820
1150 1770 2380 2780 3180 3580 3980 4370 4750 NA NA NA NA NA NA
1060 1790 2520 2670 3090 3510 3930 4350 5040

NA NA NA NA NA

NA NA NA NA NA NA

NA NA NA

NA NA NA NA

Calculated Based On 1000 FPM Velocity Through The Rectangular Damper. Zone Damper
Recommended Velocity Is 1000 – 1500 FPM. Select 1000 FPM or Less for Quiet Operation. For Other

Velocities, Use The Following Multipliers To Obtain The Correct CFM: 500 FPM = 0.5, 750 FPM =

0.75, 1250 FPM = 1.25, 1500 FPM = 1.5, 2000 FPM = 2.0, 2250 FPM = 2.25.

2.) Bypass Dampers Should Be Selected for 60% to 70% of the HVAC Units Rated CFM Capacity.

Recommended Bypass Damper Velocity is 1750 – 2250 FPM.

NA NA

Design Guide 1-15

Section 1

Auto-Zone Basic

Pressure Independent Zone Dampers

Pressure Independent operation is only available for round zone dampers. Use the chart
below to set the calibration of the zone damper after installation.

Damper

Size

6” 474

8” 950
10” 1417
12” 2120
14” 2908
16” 3700

Flow Probe “K” Factor =

CFM @ 1” Velocity Pressure

Table 1-3: Pressure Independent Flow Factors

Flow Probe
“K” Factor

Note: K Factors are programmed for each zone so that the correct CFM will be

calculated for the different size air valves.

1-16 Design Guide

Auto-Zone Basic

Section 1

Auxiliary Heat Control
Options

The Auto-Zone Basic Control System offers you a variety of methods to deal with zone
heating requirements. When deciding how to handle zone heating requirements, you
should consider the following:

• Does the rooftop unit have heat?

• Are you using fan-powered boxes?

• Is auxiliary heat used such as baseboard or radiant ceiling panels?

If the zone has some type of heat, you must consider how the heat is to be used. Typical
questions that should be asked:

Q: Should the zone heat be used as a first stage where it will become active before a

heating demand is created at the rooftop unit?

A: This mode is useful if you expect to have both heating and cooling demands at the

same time. The zone will use its own heat and allow the rooftop unit to continue to
provide cooling for other zones. This mode is also useful if the rooftop unit does not
have any heating capabilities.

Q: Is the zone heat only to be used as a second stage where it will be activated only if

the rooftop unit cannot maintain the space temperature such as during very cold
weather?

A: In this mode of operation the rooftop will examine the heating and cooling demands

and try to satisfy all of the zones by switching between heating and cooling as
required. The zone heat will only be activated if the zone temperature falls below a
selected limit.

Q: Should the zone heat be locked out if the rooftop unit is supplying warm air?

A: In many instances, it is desirable to use the rooftop heating whenever possible and

only use zone heat when the rooftop unit is in cooling or vent mode. This often
provides the most cost-effective operation since zone heat is typically electric. This
mode of operation will lockout zone heat if the rooftop is delivering heated air.

Design Guide 1-17

Section 1

Auto-Zone Basic

Relay Expansion Board

The following describes the operation of each of the relays on the optional relay
expansion board. You can choose the appropriate relays for any given application.

Relay #1 - Parallel Fan

If the Zone is in cooling mode or vent mode, the parallel fan can activate any time the
zone temperature drops 0.5°F below the heating setpoint. It de-activates when the
temperature rises above the heating setpoint. The space temperature must be below the
AUX HEAT setpoint in the occupied mode before the Parallel Fan relay can be
energized.

Relay #2 - Box Heat

If the zone is in cooling mode or vent mode, the box heat can activate any time the zone
temperature drops 1.5°F below the heating setpoint. It de-activates when the temperature
rises to within 1.0°F of the heating setpoint. Box heat is not allowed to activate in the
heating mode when there is hot air being supplied by the air handling unit. This output
was intended to allow zone re-heat while the Zone Manager is satisfying cooling
demands in other zones. The space temperature must be below the AUX HEAT setpoint
in the occupied mode before the Box Heat relay can be energized.

Relay #3 - Aux Heat

In the occupied mode, the aux heat can activate any time the zone temperature is 0.5°F
below the aux heat setpoint. It de-activates when the temperature rises 0.5°F above the
aux heat setpoint. In the unoccupied mode, the aux heat uses the unoccupied heating
setpoint with the same deadband values mentioned above. This prevents the zone from
maintaining the same aux heat setpoint at night that it does during the daytime.

This output was intended to allow zone heating to augment the normal heating mode and
also to allow a zone an attempt to satisfy its own heating needs before creating a heating
demand at the Zone Manager.

Relay #4 - Series Fan

The series fan runs any time the main fan is running. This includes occupied and
unoccupied modes. The fan can only start running when the zone damper is closed, so it
determines that the damper is closed before starting the fan.

1-18 Design Guide

Auto-Zone Basic

Index

Section 1

1 inch W.C. ......................................... 10

After-Hours

Overrides........................................... 7

Air

Bypassing.......................................... 6

Air Motion .......................................... 11

Auto-Zone Plus System ........................ 8

AUX HEAT

Setpoint ........................................... 18

Auxiliary Heat

Control Board ................................... 9

Control Options............................... 17

Recommendation .............................. 7

Barometric

Relief Dampers ................................. 7

Baseboard

Heat................................................. 17

Basic System

Design Guide .................................... 8

Diagram............................................. 2

Boards

Relay Expansion ............................. 18

Box Heat ............................................. 18

Building Pressurization......................... 7

Building Zones

Diagram............................................. 9

Bypass

Air ..................................................... 6

Plenum .............................................. 7

Return Air Intake .............................. 7

Bypass Damper

Overview........................................... 3

Sizing .......................................... 8, 11

Bypass Duct Size ................................ 11

Ceiling Diffuser .................................. 11

Central Unit

Sizing .......................................... 8, 10

CFM

Correct ............................................ 16

Maximum........................................ 11

Comfort............................................... 11

Cooling

Partial Load Conditions .................... 5

Cooling Load

Maximum.......................................... 8

Dampers

Slaved.............................................. 13

Design

Duct............................................. 8, 10

Room Air Motion.............................. 8

Zoning............................................... 8

Design Guide ........................................ 8

Diagrams

Basic System..................................... 2

Diffusers

Ceiling............................................. 11

High Induction ............................ 11

Selection...................................... 8, 11

Slot .................................................. 11

Dimensions

Rectangular Damper ....................... 14

Round Damper ................................ 14

Duct Design ........................................ 10

Considerations .................................. 8

Duct Static

High................................................... 6

Duct Static Pressure .............................. 3

Ducted Returns ..................................... 6

Ducts

Undersizing..................................... 10

Ductwork

Damaging.......................................... 6

Economizer

Benefits Of........................................ 6

Recommendation .............................. 5

Equipment

Oversizing......................................... 7

Exhaust

Powered............................................. 7

Exterior Zones....................................... 5

Global Override .................................... 7

Design Guide 1-19

Section 1

Auto-Zone Basic

Heat

Auxiliary ........................................... 7

Baseboard........................................ 17

Supplemental..................................... 9

Heating

Auxiliary ......................................... 17

Difficulties ........................................ 7

Partial Load Conditions .................... 7

Radiant Ceiling Panels.................... 17

Heating Load

Maximum.......................................... 8

Heating Minimum Setpoints................. 7

High Induction Diffusers .................... 11

High Pressure Switch

Manual Reset .................................... 6

Induction Ratio

High................................................. 11

Interior Zones........................................ 5

K Factors............................................. 16

Linear Slot Diffusers........................... 11

Load .................................................... 10

Diversity.......................................... 10

Load Calculation

Program........................................... 11

Load Estimating

Program........................................... 10

Lockout

Low Temp......................................... 5

Low Ambient Termperature Lockout ... 5

Low Supply Air Temperatures.............. 5

Low Temp Lockout............................... 5

Manual Reset

High Pressure Switch........................ 6

Maximum

CFM ................................................ 11

Cooling Load .................................... 8

Duct Velocity.................................. 10

Heating Load..................................... 8

Mechanical Safeties .............................. 5

Mutliple Zones...................................... 8

Negative Pressure Area....................... 12

Noise Levels ......................................... 6

Noise Problems ................................... 10

Operation

Quiet................................................ 10

Override

After-Hours....................................... 7

Conditions......................................... 7

Global................................................ 7

Oversizing

Equipment......................................... 7

Unit ................................................... 6

Overview

Auto-Zone System ............................ 3

Bypass Damper ................................. 3

Zone Controller................................. 3

Zone Manager ................................... 3

Zone Sensor ...................................... 4

Parallel Fan ......................................... 18

Partial Load Conditions ........................ 5

Aggravated........................................ 7

Heating.............................................. 7

Plenum Returns..................................... 6

Powered Exhaust................................... 7

Pressure Dependent............................. 10

Pressure Independent

Flow Factors ................................... 16

Zone Dampers................................. 16

Pressurization

Building ............................................ 7

Problems

Noise ............................................... 10

Program

Load Calculation............................. 11

Load Estimating.............................. 10

Quiet Operation................................... 10

Radiant Ceiling Panels........................ 17

Rectangular Damper

Dimensions ..................................... 14

Selection.......................................... 15

Relay Expansion Board ...................... 18

Relief Dampers

Barometric......................................... 7

Returns

Ducted............................................... 6

Plenum .............................................. 6

Room Air Motion................................ 11

Design ............................................... 8

Round Air Damper

Dimensions ..................................... 14

1-20 Design Guide

Auto-Zone Basic

Section 1

Selection.......................................... 15

Safeties.................................................. 5

Selection

Diffuser ....................................... 8, 11

Rectangular Damper ....................... 15

Room Air Motion............................ 11

Round Air Damper.......................... 15

Series Fan............................................ 18

Boxes............................................... 11

Setpoints

AUX HEAT .................................... 18

Heating Minimum............................. 7

Static Pressure................................... 6

Sizing

Bypass Damper ........................... 8, 11

Central Unit................................. 8, 10

Zone Dampers............................. 8, 13

Slaved

Dampers .......................................... 13

Slot Diffusers ...................................... 11

Linear .............................................. 11

Static Pickup Probe............................. 12

Static Pressure

Setpoint ............................................. 6

Setting ............................................... 7

Static Pressure Sensor........................... 3

Location .......................................... 12

Stratification........................................ 11

Supplemental

Heat................................................... 9

System

Design Guide .................................... 8

Overview........................................... 3

Performance ...................................... 9

Temperatures

Low Supply Air................................. 5

Temperature Lockout

Low Ambient .................................... 5

Undersizing

Ducts ............................................... 10

Units

Oversizing......................................... 6

Velocity

Maximum Acceptable..................... 13

Zone

Comfort............................................. 8

Design ............................................... 5

Diversity............................................ 5

Zone Controller

Overview........................................... 3

Zone Dampers

Pressure Independent ...................... 16

Sizing .......................................... 8, 13

Zone Heating

Auxiliary ......................................... 17

Zone Manager

Overview........................................... 3

Units Per ........................................... 8

Zone Sensor

Overview........................................... 4

Zones

Divided.............................................. 8

Exterior ............................................. 5

External............................................. 9

Interior .............................................. 5

Internal .............................................. 9

Multiple............................................. 8

Number Of ........................................ 8

Overlapping ...................................... 8

Perimeter........................................... 9

Zoning

Design ............................................... 8

Design Guide 1-21

Section 1

Auto-Zone Basic

1-22 Design Guide

Section 2

Table of Contents

Tips Before Beginning Installation..................................1

Zone Manager ..................................................................3

Communications Loop .....................................................8

Communications Loop Wiring Overview........................................................................9

Bypass Dampers ............................................................10

Zone Dampers................................................................13

Zone Controllers ............................................................14

Room Sensors ................................................................................................................21

Supply Air Temperature Sensor ....................................................................................23

Return Air Temperature Sensor.....................................................................................24

Outside Air Temperature Sensor ...................................................................................25

Duct Static Pressure Sensor ...........................................................................................26

Auxiliary Relay Board for Zone Controllers...................28

Zone Controller Auxiliary Relay Board Operation .......................................................29

CommLink IV Interface..................................................30

Basic System Worksheet................................................................................................33

Installation and Wiring

Section 2

Table of Figures

Figure 2-1: System Overview........................................................................................2

Figure 2-2: Typical System Component Locations.......................................................2

Figure 2-3: Zone Manager Dimensions ........................................................................3

Figure 2-4: Zone Manager Component Locations.........................................................4

Figure 2-5: Zone Manager Wiring.................................................................................5

Figure 2-6: Zone Manager Address Switch Setting ......................................................7

Figure 2-7: Communication Loop Wiring, Daisy-Chain Configuration .......................9

Figure 2-8: Round and Rectangular Bypass Dampers.................................................10

Figure 2-9: Bypass Damper Wiring.............................................................................12

Figure 2-10: Round and Rectangular Zone Dampers .................................................13

Figure 2-11: Zone Controller Components.................................................................15

Figure 2-12: Zone Controller Wiring..........................................................................17

Figure 2-13: Zone Controller Address Switch Settings..............................................19

Figure 2-14: Slaved Zone Controller Wiring..............................................................20

Figure 2-15: Room Sensor Installation .......................................................................21

Figure 2-16: Room Sensor Wiring..............................................................................22

Figure 2-17: Supply or Return Air Sensor Dimensions and Installation ....................23

Figure 2-18: Outside Air Temperature Sensor Dimensions and Installation..............25

Figure 2-19: Duct Static Pressure Sensor Dimensions and Installation .....................26

Figure 2-20: Static Pressure Sensor Wiring................................................................27

Figure 2-21: Auxiliary Relay Board Layout...............................................................28

Figure 2-22: CommLink IV Interface Communication Wiring..................................30

Figure 2-23: CommLink IV Interface Connections....................................................31

Figure 2-24: CommLink IVJumper Switch Settings ..................................................32

Installation and Wiring